Long before the hit version sung by Alison Krauss sideman Dan Tyminski in 2000’s “O Brother, Where Art Thou?,” the century-old traditional song “Man of Constant Sorrow” was a standard in bluegrass circles. It’s the 10th entry in our pre-IBMA “Bluegrass for Beginners” survey. Of the countless versions in circulation, let’s go with one by the great Ralph Stanley -- which ought to put the fear of God in anyone who hears it.